This application is related to a method and apparatus for the production of radiopharmaceutical copper-67. Further, the application describes a sublimation apparatus and target assembly of the sublimation apparatus used to improve the methods of producing copper-67.
Nuclear medicine is a branch of medicine that relies on radiation to both diagnose and treat a variety of conditions, including many types of cancers, heart diseases, and other disorders. Within nuclear medicine, diagnostic or imaging techniques use radioisotopes that are either gamma or positron emitters. Typically, the majority of medical procedures involving radioisotopes are for diagnostic applications. A smaller percentage of the procedures are for therapeutic purposes. In either case, these radioisotopes are relatively short-lived (i.e., a short half-life) and are linked or conjugated to chemical compounds known as radiopharmaceuticals.
A radiopharmaceutical preferably binds to one or more sites of a tissue or cancer cell. As many cancer cells have a limited number of available binding sites, the administration of a non-labeled bio-conjugate will often times block one or more of the cellular sites. Therefore, radioisotopes used in the labeling of a bio-conjugate preferably have high specific activity to minimize the attachment of non-labeled bio-conjugates that have little to no therapeutic or diagnostic effect. With the use of a gamma-detecting camera, radiopharmaceuticals are used to construct 3-D images of different organs and tissues, thereby providing information on organ function or disease. This data may in turn be used for reliable and accurate medical diagnosis.
One such radiopharmaceutical, copper-67, has a half-life of about 62 hours, and has a gamma-ray energy suitable for imaging. Copper-67's beta particle is also of sufficient energy for therapy with a cell range of less than 2 mm and the gamma ray is detectable using a SPECT camera. In addition, the chelation chemistry of copper is well established and copper is well tolerated by the body, particularly at the trace levels administered to patients. Furthermore, a copper-67 radiopharmaceutical has sufficient range to target and irradiate small tumors without damaging surrounding healthy tissue. Copper-67 has been used in studies to treat non-Hodgkin's lymphoma and shows promise in treating many types of cancer. The half-life of copper-67 also delivers a low systematic radiation dose to the patient and allows for its transportation from a generation facility to a medical center or research laboratory.
Methods for producing copper-67 have included nuclear reactors and bombarding zinc oxide with high energy protons. Like reactor generation, producing copper-67 using high energy proton accelerators has high inherent capital and operational costs, scheduling issues, and product contamination risks. The specific activity of copper-67 from proton production methods also exhibit wide variability. As nuclear medicine continues to be an important part of non-invasive disease diagnosis and treatment, there exists the need to produce copper-67 without the described drawbacks.